Intermolecular forces strongest to weakest are ion dipole, hydrogen bonding, dipole-dipole force, and van der wall forces.

Hello, reders today here, we will discuss about the intermolecular forces strongest to weakest.

Read More:- What is the intermolecular forces of CH3Cl?

What are the Intermolecular forces strongest to weakest?

If i am talking about the sequence of strongest intermolecular forces to weakest intermolecular forces. we will discuss about properly sequence of strongest to weakest intermolecular forces.

The sequences of intermolecular forces strongest to weakest are;

1. Ion dipole force

2. Hydrogen bonding

3. Dipole-dipole force

4. Van der waals force

These are the proper and accurate sequence of strongest to weakest intermolecular forces. now, we will explain about all types of strongest to weakest intermolecular forces.

lets get started,

1. Ion dipole

Ion dipole forces are the weakest intermolecular forces. But it is strongest compare with hydrogen bonding. Yes, it is absolutely true, ion dipole forces is much weakest compare with covalent bond and hydrogen bond.

ion dipole forces mean, when ion (Catonic Or iononic such as Cl) and dipole such as (hcl) interact each other. this interaction between ion and dipole is called ion dipole forces. due to this interaction weaker intermolecular forces are generated.

let’s know with example,

First take ion (iononic) and dipole

iononic ion + dipole

where,

ion – Cl

dipole – HCl

it is iononic ion + dipole

When ion and dipole are interacted each other, then highly strongest intermolecular forces are generated between ion and dipole. this interaction between ion and dipole is shown in the figure.

Ion dipole

In case of ion dipole forces, Cl interacted with HCl it give strongest type of intermolecular forces, ion dipole forces is strongest intermolecular forces compare with hydrogen bonding. When Cl interacted with H because Cl has partial negative charge and hydrogen have partial positive charge then both Cl and Hydrogen are interact each other. Other reason is Cl is highly electronegativity atom compare with hydrogen.

therefore, after interaction between Cl and H then it gives ion dipole forces. this forces is called strongest intermolecular forces.

Other example, for ion dipole forces

ion (cationic) + dipole

where

ion – Na+

dipole – H2O (polar molecules)

When ion interacted with dipole strongest intermolecular forces are generated. because Na+ have partial positive charge and H2O have partial negative charge. It gives strongest intermolecular forces. this interaction between Na+ and H2O is shown in the figure.

Ion dipole forces

These are the best example for ion dipole forces, Na+ have partial positive charge and H2O have partial negative charge. Actually, you know that, H2O is polar molecules. and when ion is interacted with polar molecules or dipole then ion dipole forces are generated.

Yes, it is absolutely true, ion dipole forces are generated between water (H2O) molecules and sodium (Na+). both are interacted each other just because oxygen in water molecules has slightly negative charge and sodium ion (Na+) have positive charge. These intermolecular ion dipole forces are much weaker then covalent bond.

Read MoreWhat is the intermolecular forces of CH4?

2. Hydrogen bonding

Hydrogen bonds occur when hydrogen are attached with very electronegative atoms such as, nitrogen, oxygen, F. In other words, hydrogen bonding are created when if hydrogen make N-H bonds, N-O bonds or N-F bonds. You know that h2o, nh3 is best example of hydrogen bonding intermolecular forces.

for example: – NH3 molecules (N-H bonds)

hydrogen bonding occur between nh3 molecules because if you look at the structure of nh3, hydrogen are directly attached with high electronegative atom such as nitrogen (N). we know that, if any molecules bound to highly electronegative elements such as, N, O, and F then it make hydrogen bonds between molecules due to large difference of electronegativity. it mean, nitrogen is highly electronegative atom compare with hydrogen.

• If hydrogen attached with highly electronegative atoms such as, N, O, F. then this types of bonds is know as hydrogen bonding. these are the simple basic concepts of hydrogen bonding.

• the element has at least one loan pair electron.

According to difference in electronegativity between two atoms., suc as, N and H. you know that, the value of electronegative of nitrogen is 3.0 and the value electronegative of hydrogen is 2.2. it mean nitrogen has highly electronegative atoms compare with hydrogen. the difference of electronegativity between atoms is (0.8). therefore, the large difference in electronegativity between the N atom and H atom, N-O, N-F atoms leads to highly polar covalent bond. so, you can say that, it is polar molecules. and it has hydrogen bonding.

As a result, this molecules is called highly polarized molecules. in this case, partial positive charge appear on hydrogen and partial negative chare appear on nitrogen. there are two highly polarized molecules. and both are attract each other. partial positive charge of hydrogen are attracted with partial negative charge of other molecules. As a result attraction forces is produced between them. this type of forces is called hydrogen bonding. hydrogen bonding is also called intermolecular forces between two molecules.

Hydrogen bond occur between molecules that are atmos are bound to highly electronegative elements. and it has available loan pair electron. therefore, it is more possibility to make hydrogen bonding.

For example, H.F, (relationship between Hydrogen fluoride)

Relationship between Hydrogen fluoride [HF]

In case of hydrogen fluoride (HF molecules), it is chemically bounded due to covalent bond. it is share one pair of electrons and form a single molecules of hydrogen fluoride. hydrogen is directly attached with high electronegative atom(F). fluorine is highly electronegative atom compare with hydrogen. the electronegativity of fluorine is 4.0 and electronegativity of hydrogen is 2.1 and difference is (1.9). Due to large difference in Electronegativity. As a result hydrogen bonding occur between hydrogen fluoride atoms.

Hydrogen bonding
hydrogen bonding between hydrogen fluoride.

therefore, we can say that it is highly polarized molecules. partial negative charge appear on fluorine and partial positive charge appear on hydrogen. there are two polarized molecules in which they attracted partial negative charge to partial positive charge. As a result attractive force is produce that forces is called hydrogen bonding.

3. Dipole-dipole force

Mainly, dipole-dipole force occur polar molecules. dipole-dipole force are attracted between molecules. a partial positive end of one molecules to partial negative end of another molecules.

For example :- NH3, HCl and HF

Dipole-dipole intraction are attracted among polarized molecules. we know that polarized molecules has two poles partial positive pole and partial negative pole. therefore it is called dipole. dipole dipole intraction occur between two polarized molecules or between two polarized dipole.consider the one dipole, it has two pole partial positive pole and partial negative poles. consider another dipole it has also two poles, partial positive pole and partial negative poles, we has two dipoles. So, the negative pole of one molecules attracted the positive pole of another molecules. due to this attractive forces are produces. this attractive forces is called dipole dipole intraction.

For examples, (Relation of dipole dipole forces in hydrogen fluoride (HF)

similarly, consider the single molecules of hydrogen fluoride. you know that it is dipole because it has two pole partial positive pole and partial negative pole. Consider another molecules of hydrogen fluoride, these are also a dipole because it has two pole partial positive pole and partial negative pole. it has two dipole as shown in figure. the negative pole of one molecules attracted to positive pole of another molecules. due to this attractive forces produced between this two dipoles, this type of forces is called dipole-dipole intraction.

Dipole dipole forces

electronegativity is difference between H and F. so, it is a polar molecules and polar molecules have permanent dipoles and it is make covalent bond. they attract partial positive end of one polar molecules to the partial negative end of another polar molecules. therefore, we can say that, hydrogen bonding and dipole-dipole intraction are also occur in H.F ,N-H molecules.

You can identify bond type by the following electron difference such as,

> 2.0 – ionic

0.5 to 2.0 – polar covalent

< 0.5 – nonpolar covalent

Here, in case of nh3 molecules, the large difference of electronegativity (0.8) occur between the N atom and H atom. and due to above information we can say that it is polar covalent. and due to highly electronegativity atom like nitrogen (N) are directly connected with hydrogen (H). and it make N-H bond. this reson, dipole-dipole intraction and hydrogen bonding occur between nh3 molecules.

In case of NH3, both dipole-dipole intraction and hydrogen bonding are persent as well. you know that hclo intermolecular forces has also dipole-dipole intraction. if you talk about london dispersion forces, it is temporary dipoles, reson is, distribution of electron is not well on molecules. but london dispersion force is not high attraction then dipole – dipole intraction.

Some common strongest to weakest intermolecular forces, which form within molecules. such as, covalent bondionic bond, coordination bond, van der walls forces. but these force are weaker then intermolecular force. intermolecular forces are responsible for the liquid, solid, and solution state of any type of compound.

4. Van der waals forces

Van dar waals forces is weakest type of intermolecular forces. You know that this type of intermolecular forces is much weaker then covalent bond, ionic bond even hydrogen bond. van der waals forces have bond energy 8 kj/moles. it is used to find the intermolecular forces. It is also called secondary forces.

Van der waals forces occur in between class of molecules. Such as,

  1. Van der waals forces occur between 2 polar molecules and also between 2 non polar molecules.
  2. Vander waals forces also occur between ion and polar and ion and non polar.
  3. Van der waals forces molecule – molecule can be attracted. and ion – molecule can be attracted.

There are mainly three types of van der waals forces, such as

  1. London and dispersion forces
  2. Dipole dipole forces
  3. Hydrogen bond

London and dispersion forces

london and dispersion forces is weakest type of intermolecular forces. ldf are a type of forces in which they attracted between atoms or molecule that are normally electrically symmetric. in this case electrons are symmetric distributed with respect of nucleus.

London dispersion forces

Dipole dipole forces

  1. Dipole dipole forces occur between two polar molecules.
  2. Dipole-dipole intraction are attracted among polarized molecules. we know that polarized molecules has two poles partial positive pole and partial negative pole. therefore it is called dipole. dipole dipole intraction occur between two polarized molecules or between two polarized dipole.
  3. Consider the one dipole, it has two pole partial positive pole and partial negative poles. consider another dipole it has also two poles, partial positive pole and partial negative poles, we has two dipoles. So, the negative pole of one molecules attracted the positive pole of another molecules. due to this, attractive forces are produces. this attractive forces is called dipole dipole intraction.
  4. Take For examples – HCl.
  5. HCl is best example for dipole dipole forces.
  6. Cl is highly electronegativity atoms compare with hydrogen. That’s why, Cl has partial negative charge whereas, hydrogen has positive charge. due to this they attracted each other and dipole dipole forces are generated. this is shown in figure.
dipole dipole forces

Hydrogen bonding

Intermolecular forces strongest to weakest
  1. Hydrogen bonds occur when hydrogen are attached with very electronegative atoms such as, nitrogen, oxygen, F. In other words, hydrogen bonding are created when if hydrogen make N-H bonds, N-O bonds or N-F bonds. You know that h2o is best example of hydrogen bonding intermolecular forces.
  2. Hydrogen bonding occur between two polar molecules such as h2o.
  3. Let’s know with example.
  4. Here, oxygen is highly electronegativity atoms compare with hydrogen. That why hydrogen have partial positive charge and oxygen has partial negative charge. due to this, both atoms are attracted each other. and hydrogen bonding occur between polar molecules (h2o). and they make H-O bonds as shown in figure.

What are the order of intermolecular forces from weakest to strongest?

In order from weakest to strongest, the intermolecular forces are,

  1. Van der waals forces
  2. Dipole dipole forces
  3. Hydrogen bonding
  4. Ion dipoles

These are the write from weakest to strongest intermolecular forces.

What is the main types of intermolecular forces?

The main types of intermolecular forces are as follows,

  1. Ionic bonds
  2. Hydrogen bonding
  3. Van der waals dipole dipole interaction
  4. Van der waals dispersion forces (London dispersion forces)

These all types of intermolecular forces may occur between molecules. it is depend upon molecules because different molecules generate different types of intermolecular forces.

for examples,

NH3 – Hydrogen bonds, dipole dipole interaction, and dispersion forces.

CH4 – Only London dispersion forces

HF – Hydrogen bonds

& more.


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